This invention relates to ultrasonic test heads and more particularly relates to ultrasonic test heads wherein a damping body is arranged on an oscillating crystal on the opposite side from the direction of the sonic beam.
One example of such an ultrasonic test head is shown in German patent publication No. 22 17 472. This prior art ultrasonic test head includes an oscillator composed of lithium sulfate or a similar crystalline material and a damping body made from a curable synthetic resin to which a heavy metal powder is added to thereby increase the specific impedance of the casting resin. The powdery heavy metal additive comprises tungsten.
However, in order to provide a very wideband test head, it is often necessary to increase the metal powder content far beyond 50 percent by volume, which poses extremely great manufacturing difficulties. Additionally, problems are also encountered regarding the reproducibility of the device. It is therefore an object of the instant invention to provide an ultrasonic test head with a damping body which is characterized by a high acoustic impedance, having high acoustic absorption and which is easy to manufacture.